Hazardous Weather: Excessive heat with daytime highs in the 90s, and maximum heat index values near or above 100 degrees Fahrenheit, for most of the area. In addition, during the worst of the heat wave (Sunday through Tuesday), overnight low temperatures may not get below the mid 70s, especially along and southeast of the Interstate 95 corridor.
Locations affected: Much of the area has the potential to see excessive heat, with the worst conditions likely in the Wilmington-Philadelphia-Trenton urban corridor, and in northern Delmarva. Locations right along the coast and in the higher terrain of the southern Poconos and far Northwest New Jersey may fall short of excessive heat criteria.
Timing: Starting this weekend and continuing through the middle of next week. The worst of the heat wave looks to be on Monday.
Impacts: These heat index values can cause heat related stress particularly among the at-risk populations. Those especially vulnerable include elderly, children, those with pre-existing conditions, especially if they live near urban centers without air conditioning.
Confidence on occurrence: We have high confidence that we will see excessive heat for much of this period. However, exact temperatures and heat index values will be dependent on the amount of cloud cover and how widespread thunderstorms are each day, which remains uncertain.